Industrial Practices and Criteria Against Cascading Failures

Modern power grid is designed to withstand n-1 and credible n-2 outages. The ability of a grid to survive extreme outages and major disturbances is not comprehensively studied by planners and operators today. Most large blackouts that happened throughout the world involve a sequence of cascading outages that are complex and require adequate methodologies and tools to be addressed properly. Cascading outages expose transmission planners and operation engineers to new challenges, including identifying means to minimize the cascading vulnerability impacts. Understanding the effects of cascading on vulnerabilities of power grid is needed to determine when a disruption of service is likely to occur and to apply appropriate mitigation measures to reduce the associated risk. This chapter covers key topics related to the cascading outages such as development of cases, system operating states, potential chain of cascades starting with an initiating event and ending with final operating conditions, standards related to the cascading, a brief review of cascading methodologies, and tools and industry practices in the analysis of cascading outages. Through various case studies and results, power industry practitioners have demonstrated the benefits of performing cascading analysis in planning and operation.